Modular computer system having self contained workslate unit detachably coupled to base unit including keyboard

ABSTRACT

A computer base unit has a keyboard and computer peripherals. A removable workslate, capable of stand-along operation and containing a digitizer display, computer and rechargeable power supply attaches to the base unit through an interlocking connector that holds the workslate in a tilted position and connects the base unit and its peripherals to the workslate computer. The base unit and workslate comprise housings are constructed of a composite comprising layers of woven, resin impregnated fibers and a layer of electromagnetic shielding.

This is a continuation of Ser. No. 739,984, filed Aug. 2, 1991, nowabandoned.

FIELD OF THE INVENTION

This invention relates to the field of computer systems and morespecifically to an improved modular computer system which may be used ineither portable or desktop modes and which is highly resistant tohostile environments.

BACKGROUND OF THE INVENTION

Personal computers have recently become very popular for a variety ofuses ranging from home, office, engineering, sales, marketing, andmilitary applications. Virtually every aspect of business, engineeringand science utilizes some form of computer system on a daily basis.Since their introduction, personal computers have become increasinglycompact while simultaneously becoming increasingly powerful.

Conventional personal computers are typically configured with some typeof display unit, a keyboard, and some form of housing incorporating amicroprocessor, memory, disk storage devices, etc. In typical portablecomputers, the keyboard and computer electronics are incorporated in abase unit wherein a display device such as a liquid crystal display(LCD) is attached to the base unit with a hinge mechanism forming aconfiguration referred to as a "clam shell" housing. Virtually everyportable computer available today utilizes the "clam shell"configuration.

While the "clam shell" configuration provides certain advantages, italso poses several problems. First, the display unit and processor unitcannot be used apart from the base unit and keyboard. Furthermore, giventhe premium placed on optimizing the weight of the overall computersystem, current portable computer designs are relatively fragile andhighly susceptible to damage due to mechanical shocks. Finally, sincethis configuration of portable computer provides openings in the housingfor insertion of floppy disks, etc., these computer systems aresusceptible to damage from humidity, and airborne pollutants, etc.

In yet another aspect of portable computer design, recent activities inthe computer industry have been directed toward new types of inputdevices such as computer screens responsive to inputs from stylusdevices or tactile inputs. In these systems, the need for a computerkeyboard is greatly reduced or may be eliminated entirely. Accordingly,portable computers having integral keyboards are unnecessarily heavy andlarge for these applications. One well-known design goal for portablecomputers is that the computer system be no larger than a letter-sizenotebook. The incorporation of a keyboard in notebook-sized computersnecessarily complicates this design goal.

While notebook-sized computers provide the advantages of portability andcompact size, many users prefer desktop models which typically providelarger keyboards, unlimited power capabilities, and expanded peripheralsupport. Accordingly, the design goals for portable and desktop computersystems are often incompatible.

From the foregoing, no computer system is known which provides all ofthe advantages of a portable or notebook computer design, whileincorporating an enclosure structure which is weatherproof and highlyresistant to mechanical shock, while also being adaptable to desktopapplications. The computer design of the present invention provides astructure which optimizes the design goals of both portable and desktopdesigns by providing a modular computer design which may be used in aportable mode or on a desktop, either with or without a keyboard.

SUMMARY AND OBJECTS OF THE INVENTION

In summary, the modular computer system of the present invention in apreferred embodiment includes a self-contained workslate unit having ahousing; a display unit visible at a surface of the housing; input meanspreferably including a digitizer disposed in cooperative engagement withthe display unit, a processing apparatus having an address and data bus,serial and parallel ports, modem, video and a keyboard interface, theprocessing apparatus system for outputting display data to the displayunit and for receiving input data from the input means, digitizer and/orkeyboard as well as for providing computer functions to a user includingbi-directional data communications via the modem and the respectiveserial and parallel ports; and a mass data storage device coupled to thecomputer. The workslate unit further includes first connector means forproviding connections for the computer data and address bus, therespective serial and parallel ports, modem, display data and thekeyboard interface.

The workslate unit is adapted for use with one of several base unitshaving a keyboard, and an expansion area for supporting one or moreperipheral devices. The desktop base unit includes a docking means forengaging the workslate unit, the docking means including secondconnector means for coupling to the first connector means providingelectrical connections for the keyboard and said one or more peripheraldevices, display data, modem, address and data bus and the respectiveserial and parallel ports. The docking means further includes means formechanically attaching the workslate unit to the desktop base unit.

The present invention further provides a multi-layer composite housingstructure for housing the respective components of the presentinvention, comprising a relatively high density layer forming anexternal surface of the housing, a first layer of woven structural fibermaterial overlaying the relatively high density layer, a layer of closedcell foam material overlaying the first layer of structural fibermaterial, preferably woven, a second layer of woven structural fibermaterial overlying the layer of closed cell foam material, a layer ofelectromagnetic shielding material overlying the layer second layer ofwoven structural material, and a third layer of woven structural fibermaterial, wherein first, second and third layers of woven structuralfibers, said layer of electromagnetic shielding and said layer of closedcell foam material of said composite housing are permeated with athermoset resin, such as acrylic epoxy, vinylester or polyester forbinding all the respective layers of the composite housing together.

Accordingly, it is an object of the present invention to provide amodular computer system which may be used in both portable or desktopmodes.

It is another object of the present invention to provide a computersystem which may be used either with or without a keyboard.

It is still another object of the present invention to provide anenclosure for a computer system which is highly resistant to mechanicalshocks.

It is yet another object of the present invention to provide a modularcomputer system having an improved docking system for uniting therespective modular components of the present invention.

It is still another object of the present invention to provide acomputer system which is highly resistant to damage from moisture andairborne pollutants.

It is still another object of the present invention to provide acomputer system which is compact and powerful.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects may be fully understood through the detaileddescription of the invention set forth below and the accompanyingdrawings in which:

FIG. 1 is a front view in perspective of the modular computer system ofthe present invention showing the workslate unit attached to the baseunit.

FIG. 2 is a rear view in perspective view of the modular computer systemof FIG. 1.

FIG. 3 is a side view of the modular computer system of FIGS. 1 and 2.

FIG. 4 is a view in perspective of the modular computer system of thepresent invention wherein the workslate unit is separated from thedesktop base unit.

FIG. 5A is an exploded view in perspective of the front display portionof the workslate unit.

FIG. 5B is an exploded view in perspective showing the arrangement ofcomponents in the rear portion of the workslate unit.

FIG. 5C is a side view showing the arrangement for mounting the massdata storage device in the rear portion of FIG. 5B.

FIG. 5D is a top view showing the arrangement of components of theworkslate unit.

FIG. 6A is a view in perspective of the workslate connector plate andassociated docking assembly.

FIG. 6B is a front view of the workslate connector plate.

FIG. 7 is a cutaway view of the assembled workslate unit taken alongsection 7--7 in FIG. 1.

FIG. 8 is an exploded view in perspective of the desktop base unit usedin conjunction with the workslate unit of FIGS. 2 and 3.

FIG. 9 is a view in perspective of the docking assembly of FIG. 6A andFIG. 8.

FIGS. 10A and 10B are side views detailing the operation of the dockingassembly of FIG. 6A and FIG. 8.

FIGS. 10C-10D are side view of a latching control mechanism which may beused with the docking assembly of FIGS. 10A-10B.

FIG. 10E is a top view of the latching control mechanism of FIGS.10C-10D.

FIGS. 11A-11C are side views of base members used for securing thedocking assembly to the base unit.

FIG. 12, a cross-sectional view taken along section 12--12 in FIG. 1,shows operation of the docking assembly with the workslate attached tothe base unit.

FIG. 13A is a block diagram of the electrical components of theworkslate unit of the present invention.

FIG. 13B is block diagram of the motherboard components of FIG. 13A.

FIG. 13C is a block diagram of the electrical components of the desktopbase unit of the present invention.

FIG. 14 is a schematic and block diagram of the digitizer of FIG. 5A.

FIG. 15A is a cross-sectional view detailing the process used formanufacturing the multi-layer laminate structure of the housing membersof the present invention.

FIG. 15B is a cross-sectional view of the multi-layer laminate structureresulting from the process described in conjunction with FIG. 14A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides an improved modular computer system 10which may be used as either a self-contained workslate or tablet unit,or in the alternative, as a complete desktop unit which includes a basehaving a keyboard as well as support for a variety of peripheralcomponents. Referring now to FIGS. 1-4, the improved modular computersystem 10 comprises a self-contained workslate unit 12 which may beremovably attached to base unit 14. The workslate unit 12 comprises afully functional computer system which is described in detail below. Thebase unit 14 incorporates a full size alphanumeric keyboard 16 andprovides connections for various signals through connector area 18.Specifically, connector area 18 provides connectors for a telephone jack20, a connector 22 which provides parallel port connections, a connector24 for serial port connections, a connector 26 for display dataconnections, and a power connector 28. In one embodiment, connectorplate 18 may be modified to include a connector (not shown) to provideconnections for the full computer address and data bus. A variety ofperipheral components may be disposed in storage area 30. For example,it is contemplated that peripheral devices such as a disk drive 32 and anumeric keypad (not shown) may be disposed in storage area 30. As shownin FIGS. 1-3, storage area 30 is relatively compact to enable a baseunit 14 to be used in a portable mode. Those skilled in the art willappreciate that storage area 30 may be enlarged to include a structurefor accommodating a wide variety of well-known expansion cards. As willbe further described below, in the preferred practice of the presentinvention, workslate unit 12 may be removably attached to base unit 14via a docking assembly 36 which includes a support flange 38, anelectrical connector 40 for coupling the respective components ofworkslate unit 12 and base unit 14, and a plurality of latching posts42, 42' for securing workslate unit 12 to base unit 14 (FIG. 4). Thedocking assembly 36 provides multi-position, pivoting, mechanical andelectrical attachment for workslate 12 and base unit 14. The detailedconstruction and operation of docking assembly 36 is discussed infurther detail below. In the preferred practice of the presentinvention, the workslate unit 12 is adapted for use with a stylus 45 toallow control and use of workslate unit 12 without the need for keyboard16. It is contemplated that stylus 45 may be used for entering both textand graphic information as well as any of a number of computer controlcommands.

Referring now to FIGS. 5A-5D, workslate unit 12 comprises a fullyfunctional computer system which may be used with or without a keyboard.In the preferred practice of the present invention, workslate unit 12 isprovided with means, responsive to inputs from a stylus for inputtingboth alphanumeric data as well as computer commands. Workslate unit 12comprises front and rear sections 44, 46, respectively, which are matedto form workslate unit 12. Front section 44 includes an outer housingmember 48 which includes a display area 50. A plate of protective glassor plastic 52 is attached to the perimeter of display area 50 with aring of pliable adhesive 56 which provides a shock resistant junction.In the preferred practice of the present invention, an adhesivedesignated SCOTCH Brand VHB 4910, available from Minnesota Mining andManufacturing, Minneapolis, Minn. is used for adhesive ring 56. Amounting ring 58 is then disposed concentrically about plate 52 toprovide a level surface for mounting the remaining components. Mountingring 58 is preferably attached to outer housing member 48 withconventional adhesive or formed as an integral part of outer housingmember 48. A liquid crystal display (LCD) panel 60 is then disposed overmounting ring 58. In the preferred practice of the present invention, anLCD panel of the type LMG9050ZZFC available from Hitachi Mobara Works,Hitachi, Ltd., Mobara City, Japan, is used for LCD panel 60. LCD panel60 provides a display surface 64 providing the capability to control anddisplay approximately 1024 ×768 pixels and may be used to display eithertext or graphic information. Digitizer 62 is secured to the rear of LCDpanel 60. Digitizer 62 comprises an area of orthoganally organizedconductive strips 66 coupled to appropriate decoder circuitry 68 whereindigitizer is responsive to inputs from stylus 45 to generate signalsrelated to the position of the stylus 45 with respect to display surface64. Thus, when used with appropriate software, digitizer 62 may be usedto input text or graphic information, as well as computer controlcommands. For example, handwriting recognition software such as the"NESTOR-WRITER" handwriting recognition program available from Nestor,Inc., Providence, R.I., may be used in conjunction with digitizer 62 toenable workslate 12 to be used as a tablet which responds to handwrittencharacters formed over digitizer 62 (FIG. 1). As information is enteredin digitizer 62, it is simultaneously displayed on display 60 to enableusers to visualize information which has been entered.

LCD display 60, and digitizer 62 are secured to outer housing member 48with a shock absorbing gasket 69 and a collar member 70. Collar member70 is formed with a plurality of vertical walls 72-78 which form aperimeter which engages the outer edges of digitizer 62, LCD panel 60and shock absorbing gasket 69. Flanged retaining walls 80-86 are joinedto vertical walls 72-78, respectively, to form a retaining surface forsecuring LCD display 60, digitizer 62, and shock absorbing gasket 69 tomounting ring 58. Specifically, a plurality of aligned apertures aredisposed in each respective corner of LCD display 60, digitizer 62,shock absorbing gasket 69 and collar member 70 (e.g. apertures 88-92 ofshock absorbing gasket 69, apertures 94-98 of LCD panel 60, apertures100-104 of digitizer 62, and apertures 106-110 of collar member 70). Aplurality of fasteners (e.g. fasteners 107, 109, and 111) are thendisposed through the respective apertures 88-92, 94, 96, 98, 100-104 and106-110 to secure LCD display 60, digitizer 62, and collar member 70 tomounting ring 58. In the preferred practice of the present invention, aplurality of threaded inserts (e.g. threaded inserts 93, 95, 97) may bepressed into mounting ring 58 for receiving fasteners 107, 109 and 111.Electrical connections for LCD panel 60 are provided by electricalconnector 112 and electrical connections for digitizer 62 are providedby electrical connector 114. The specific connection and operation ofelectrical connectors 112 and 114 are discussed in further detail below.The resulting fully assembled structure of front section 44 is shown inFIG. 7.

Referring now to FIG. 5B, rear section 46 of workslate unit 12 includesan outer housing section 118 which mates with outer housing member 48.Front section 44 and rear section 46 are joined to form workslate unit12. Specifically, an offset lip 120 formed integrally with outer housingmember 118 is engaged with the interior wall of outer housing member 48to join the respective sections. Connector plate 122 is disposed alongone edge of outer housing member 118 to provide a support surface forelectrical connectors which are discussed in further detail below.Motherboard 124 is disposed adjacent to connector plate 122. Motherboard124 comprises a complete computer system including a microprocessor andall essential support components discussed in detail below. In addition,motherboard 124 includes a modem 126, as well as power managementcircuitry 128. Motherboard 124 is also adapted to receive memoryexpansion board 130 which may be attached to motherboard 124 in aconventional "piggyback" arrangement via connectors 132, 134.Motherboard 124 may be attached to outer housing section 118 viafastener and spacer posts assemblies (i.e. fasteners 136, 138 and spacerpost 140). Similar fastener and spacer post combinations may be used tosecure motherboard 124 at attachment points 142, 146, 148.

A mass data storage device 150 such as a hard disk drive is disposed inouter housing member 118 as shown in FIG. 5C. Mass data storage device150 is preferably of the type MD260/MD2100 available from ArealTechnology, San Jose, Calif. A plurality of mounting brackets 152, 154having a generally "L" shaped cross-section are used for securing massdata storage device 150 to outer housing section 118. Specifically,shock absorbing grommets (e.g. grommets 156, 158) are mounted inapertures of brackets 152, 158. Conventional fasteners (e.g. fasteners160, 162) secure brackets 152, 154 to mass data storage device 150through grommets 156, 158. Brackets 152, 154 may be secured to outerhousing member 118 with adhesive strips 164, 166, respectively (FIG.5C).

A rechargeable battery pack 168 is disposed within battery cavity 170which is formed integrally in or made separately and fastened to outerhousing member 118. A removable battery door 172 may be provided for theremoval and replacement of battery pack 168. In the preferred practiceof the present invention, battery pack 168 comprises fifteen cells ofthe type KR1700AE, available from Sanyo Energy Corp., San Diego, Calif.,wherein each of the respective cells are coupled in series to provide anominal output voltage of approximately 22.5 volts. A layer ofconventional heat shrink type material 174 may be disposed about therespective cells to retain the cells in a predetermined orientation.

Outer housing member 118 further includes a cavity 176 for storingstylus 45. Stylus 45 is preferably of the electromagnetic type.

Motherboard 124 further includes a plurality of attachment areas forreceiving electrical connections from the connector plate 122 as well asthe respective computer support components. Referring now to FIGS. 5B,5D, 6A and 6B, connector plate 122 includes the following: aconventional sealed 9 pin "D" type connector 200 which is coupled tomotherboard attachment area 202 with conventional means; a sealed powerconnector 204 of the type DEE102A052, and available from W.W. Fisher SA,Apples, Switzerland, coupled to motherboard attachment area 203 withconventional means; a sealed 8 pin circular DIN connector 206 coupled tomotherboard attachment area 205 with conventional means; a sealedconventional RJ-11 telephone jack 210 coupled to modem circuitry 126 viashielded cable 211; a multi-pin connector 212 of the type Micropax 200,available from Dupont Electronics coupled to motherboard attachment area214 via conventional ribbon cable 216; a 25 pin sealed "D" typeconnector 218 coupled to motherboard attachment area 220 withconventional means; and a 15 pin sealed high density "D" type connector222 coupled to keyboard attachment area 224 with conventional means.Mass data storage device 150 is preferably attached to motherboardattachment area 226 via flexible printed circuit 228 to provide a degreeof shock isolation between the motherboard and mass data storage device150. Similarly, rechargeable battery pack 168 may be attached to powermanagement circuitry 128 via conventional cable 230.

Those skilled in the art will appreciate that any of a number of meansmay be employed for attaching the respective connectors and cables tomotherboard 124. For example, it is anticipated that connectors 200,204, 206, 218 and 222 comprise conventional printed circuit boardmounted connectors having angled leads 232, 233, 235, 234 and 236,respectively, (FIG. 6A) which may be directly soldered to conventionalprinted circuit-type plated through openings in motherboard 124, thusproviding both electrical connection and mechanical stability. Theflexible printed circuits 216, 228 may be coupled to the motherboard 124either by soldering the respective conductors directly to motherboard124 or via conventional detachable male/female connectors (not shown)disposed on the respective cables and motherboard, respectively.

In the preferred practice of the present invention, each of therespective connectors 200, 204, 206, 210, 212, 218 and 222 are coupledin watertight engagement with connector plate 122 to provide a barrierfrom moisture and atmospheric pollutants from entering the interiorportion of workslate 12. As is most clearly seen in FIG. 6B, connector222 is preferably used for coupling video and display information toworkslate 12; connector 218 provides parallel port connections;connector 204 provides D.C. power connections; connector 206 provideskeyboard connections; connector 210 provides telephone and modemconnections; and connector 200 provides serial port connections. Thisarrangement allows workslate unit 12 to be used as a stand alone unitwith the capability of interfacing to a wide variety of supportcomponents. In addition, connector 212 provides means for interfacingworkslate unit 12 to base unit 14 as is further discussed below. It iscontemplated that in addition to all of the connections mentioned above,connector 212 also includes connections for the complete address anddata bus for the computer system housed in workslate 12.

Referring again to FIG. 6A, the connector plate 122 has a generally "L"shaped cross-section formed by approximately perpendicular flangedmembers 302, 304. Flanged section 304 may be attached to outer housingmember 118 with a layer of adhesive 306. In the preferred practice ofthe present invention, connector plate 122 is formed of a heatconductive material such as aluminum or steel. Accordingly, it isanticipated that connector plate 122 also provides a heat sinking ordissipating function for workslate unit 12. In addition to supportingthe respective electrical connectors mentioned above, flanged section302 further includes mounting area 400 for attaching workslate unit 12to base unit 14. Specifically, mounting area 400 is formed integrallywith flanged section 302 and includes a region 402 having a relativelylarge cross-sectional area with respect to the remainder of flangedsection 302. Cavity 404 is formed within region 402 wherein a portion ofconnector 212 extends into cavity for mating with connector 40 ofdocking mechanism 36. A plurality of lateral struts 406, 408 may beprovided for securing connector 212 to area 402 to provide mechanicalstability when mating connectors 40 and 212. In the alternative, amounting flange (not shown) may be disposed about the periphery ofconnector 212 for mounting connector 212 to connector plate 122. Area402 further includes a plurality of tapered bores 410, 412 forcomplementing and receiving latching posts 42, 42', respectively.Tapered bores 410, 412 include annular channels 414, 416 for receivinglocking bearings 418, 420, which are further discussed below. Annularchannel 416 is most clearly seen in FIG. 7. In the alternative, aplurality of sealed inserts (not shown) may be inserted into taperedbores 410, 412 to seal tapered bores 410, 412 from the environment. Therespective sealed inserts may be in the form of resilient plugs or mayalternatively comprise permanently installed having an interior cavitywhich complements the exterior shape of latching posts 42, 42'.

Once the front and rear sections 44, 46, respectively, are assembled,they are mated together as shown in FIG. 7. The resulting workslatestructure is extremely compact, and stable. Front and rear sections 44,46 may be joined with any of a number of conventional means includingadhesive or frictional attachment or in the alternative, conventionalfasteners (e.g. fastener 424) may be disposed about the periphery ofworkslate unit 12 engaging outer housing 48 and flanged section 120 intothreaded inserts (e.g. threaded insert 425) pressed into the respectivevertical walls of collar member 70. Regardless of the specific method ofattachment, it is contemplated that front and rear section 44, 46 areformed in watertight engagement.

Referring now to FIG. 8, the base unit 14 comprises an outer housing 450which is preferably formed with the same material used for fabricatinghousing members 48, 118. Docking assembly 36 is pivotally secured tohousing member 450 with hinge support members 452, 454 which are securedto housing member 450 with conventional fasteners 456-462. Assembly 470is then secured to housing member 450. Assembly 470 includes keyboardmounting bracket 472 which includes a plurality of mounting posts (e.g.mounting posts 474) for receiving keyboard 16. Keyboard 16 is formed asa single module of the type U04003001 available from Keytronic, Spokane,Wash. A finishing collar 476 is secured to keyboard mounting bracket 472with conventional mounting posts 478 which may be secured betweenmounting bracket 472 and finishing collar 476 with conventional means. Arear cover 480 is attached to finishing collar 476 via finishingbrackets 482, 484 which are adapted to cover areas 486, 488,respectively, of housing 450. Finishing brackets 482, 484 may be securedto rear cover 480 and finishing collar 476 with conventional means. Rearcover 480 includes integral mounting flanges 490, 492 for mountingfloppy disk drive 32. Rear cover 480 further includes integral mountingflanges 496, 498, wherein assembly 470 may be secured to housing member450 with conventional fasteners 502 which engage threaded inserts 479 inmounting flanges 496, 498 through apertures 504, 506 and which engagethreaded inserts 479 in mounting bracket 472 through apertures 508-514.Additional fasteners (not shown) may be provided for securing portion516 of cover 480 to housing member 450.

Referring now to FIG. 9, 10A-10B and 11A-11C, docking mechanism 36includes a support flange 38 which is pivotally attached to housingmember 450 with hinge support members 452, 454. Support flange 38includes a base portion 520 and a rear support portion 522 which form acomplementary shape with respect to connector plate 122. Latching posts42, 42' are disposed within recesses 524, 526, respectively, and may besecured to base portion 520 with flanges (e.g. flange 527, FIG. 10) andconventional retaining rings 528, 530, respectively. Electricalconnector 40 is secured to base portion 520 with support posts 532, 534which are secured between electrical connector 40 and base portion 520with conventional means. Conventional flexible circuit 536 is coupled toelectrical connector 40 and extends through aperture 538 to coupleelectrical connector 40 to connector plate 18, to floppy disk drive 32,and keyboard 16 or any of a variety of other peripheral components.Those skilled in the art will appreciate that flexible printed circuit536 may comprise single or multiple sections of flexible printedcircuits which are routed separately to the respective components ofbase unit 14. A plurality of rearwardly extending flanges 540, 542 areformed integrally with support flange 38 to provide control surfaces forcontrolling the pivotal position of docking mechanism 36. Specifically,a plurality of angularly offset detents 544 are disposed in therespective faces of flanges 540, 542. Hinge support members 452, 454 arepivotally coupled to support flange 38 with axially disposed pivot posts545, 546 which are received in annular bores (e.g. annular bore 548 ofsupport flange 38). Each pivot post includes a threaded portion 550, 552which threadably engages base members 452, 454, respectively (FIGS.11A-11C). In addition, spring loaded ball bearing members 554, 556 arethreadably disposed in hinge support members 452, 454, respectively,wherein each respective ball bearing member includes an outwardly biasedball bearing 560, 562 which engages one of the respective plurality ofdetents 544 as support flange 38 is pivoted between a plurality ofpredetermined positions. As support flange is pivoted between positions,each respective spring biased ball bearing is compressed slightly untilit engages the next adjacent detent. Accordingly, a plurality ofpivoting positions are provided with each respective position defined bythe relative position of the respective detents 544 on the respectiveflanges 540, 542.

Referring now to FIGS. 10A and 10B, in another aspect of the presentinvention, each of the respective latching posts 42, 42' are providedwith a means for positively locking workslate 12 to base unit 14. Asnoted above, each respective latching post 42, 42' is provided withlatching bearings 418, 420 which engage annular channels 414, 416 ofconnector plate 122. Since latching posts 42, 42' are identical, onlythe operation of latching post 42 is discussed herein. Latching bearings418 operate in either latched or retractable modes as controlled by aspring loaded, axially disposed control rod 570. Control rod 570includes an axial recessed area 572 which allows the respective latchingbearings 418 to retract, and further includes a portion 574 which urgesthe respective latching bearings outwardly. When support flange 38 ispositioned so that workslate unit 12 is substantially vertical, controlrod is urged upwardly via contact with housing 450, thus compressingbiasing spring and bringing axial recessed area 572 into alignment withlatching bearings 418, thus permitting latching bearings 418 to retractinto latching post 42, as shown in FIG. 10A. In this position, workslateunit 12 may be readily inserted onto or removed from latching posts 42.As shown in FIG. 10B, as support flange 38 is pivoted, control rod 570is urged outwardly by bias spring 576, thus forcing portion 574 intoalignment with latching bearings 418, thus locking latching bearings 418in the fully extended position. In this position, latching bearingsengage annular channels 414, 416, thus locking workslate unit 12 tosupport flange 38.

The respective latched unlatched positions of workslate unit 12 are mostclearly seen in FIG. 12. In position 580, workslate 12 is in asubstantially vertical position wherein control rod 570 engages housingmember 450, thus permitting latching bearings to retract. As workslateunit 12 is pivoted to position 582, control rod 570 is urged outwardly,thus locking workslate unit 12 to base unit 14. At the same time thepivotal position of workslate unit 12 is controlled by the relativeposition of detents 544 with respect to hinge support members 452, 454.

An optional latching control lever 590 may also be provided as shown inFIGS. 10C-10E. In this embodiment, latching control lever 590 islongitudinally disposed beneath the respective control rods (e.g.control rod 570) wherein latching control lever 590 includes a pluralityof recessed areas 592, 594 which allow the respective control rods toextend to the latched position regardless of the relative position ofworkslate 12. Workslate 12 may then be unlatched by placing workslate 12in the substantially vertical position and by sliding control lever 590so that the respective control rods engages leveled edges 596, 598, thusurging the respective control rods to the unlatched positions.

Referring now to FIGS. 13A and 13B, the workslate 12 contains a fullyfunctional computer system 702 including the major components shown inFIG. 13B. Computer system 702 is connected to a display 60, digitizer 62and a mass data storage device 150. In addition, workslate unit 12includes a rechargeable battery pack 168. The external connections forsystem 700 are provided by the connectors located on connection plate122. Motherboard 124 incorporates computer system 702 and expansionmemory 132, modem 126, power management circuitry 128 and serial andparallel ports 704, to which computer system 702 is connected.

As shown in FIG. 13A, computer system 702 comprises a conventional INTEL1386 microprocessor 706, an INTEL 1387 coprocessor 708, and an Intel82360SL support integrated circuit 710. Support circuit 710 includesserial and parallel port interfaces and a real time clock. Computersystem 702 further includes an 82456 display driver with memory 712.Display driver 712 is available from Chips Technologies, Sunnyvale,Calif. The computer system BIOS software is stored in ROM which may beof the type 27020 available from Intel. Power management circuitry 714includes an array of conventional switching transistors responsive tosignals generated by support integrated circuit 710 to selectively applypower to the respective components of workslate 12. Power manager 716further includes a conventional step down regulator type DC-DC convertorfor converting the power produced by battery pack 168 to the appropriatelevel. Modem 126 may incorporate conventional means to provide highspeed data communication as well as compatibility with conventionalfacsimile systems. Computer system 702 is further coupled toconventional RAM 130. Computer system 702 further includes disk drivecontrollers 726 for controlling the respective disk drives, and akeyboard and function controller 726 for controlling the keyboard 16 andsuch parameters as the brightness and contrast of LCD display 60. Ananalog to digital converter 730 is provided for sensing various analogfunctions such as the battery pack operating voltage. Finally, expansionport controller 718 is provided for controlling digitizer 62.

Those skilled in the art will appreciate that the respective componentsof motherboard 124 may readily be connected on a conventional printedcircuit board using well-known techniques. The respective data manualsfor each of the components of motherboard 124 provide the informationregarding the specific interconnections for system 700.

The base unit electronics 750 (FIG. 13C) includes keyboard 16, anoptional numeric keypad 752, and a floppy disk drive 32. Base unit 14further includes docking unit connector 40 and expansion connectors 18discussed above. The base unit 14 may be readily modified to include anyof a number of additional peripheral components (not shown).

Referring now to FIG. 14, the digitizer 62 includes an array oforthogonally organized rows and columns 760, 762 of overlying conductivestrips, forming an grid of X-Y intersections defining specific locationson the digitizer. The respective conductive strips are coupled tosensing amplifiers 764-774 which sense the electromagnetic signal 776induced into the conductive strips by stylus 45 which generates a tinyelectromagnetic field 776 in an area proximate its tip. Thiselectromagnetic field is of sufficient intensity to penetrate display 60and induce sufficient current flow in the respective conductive stripsto activate sensing amplifiers 764-774 coupled to each respective rowand column thus generating positional information processed by row andcolumn 778, 780 decoders. The decoded signals are then converted to aserial data stream by parallel to serial convertor 780. The output ofparallel to serial converter is coupled to motherboard 124. One exampleof a device which may be used for digitizer 62 may be fully understoodby reference to U.S. Pat. No. 4,786,765, incorporated herein byreference.

Referring now to FIGS. 15A and 15B, the respective housing elements ofthe present invention are fabricated with a multi-layer compositestructure which is both light weight and extremely resistant tomechanical shock. The composite structure 850 is formed with thefollowing process. Male and female mold elements 802, 804 are formedwith positive and negative impressions, respectively, of the housingelement being formed. A layer of gelcoat material 806, approximately0.105 inches thick is deposited in negative mold element 804. In thepreferred practice of the present invention, a material designated FerroOrthophalic gelcoat, available from Ferro Corp. is used for gelcoatlayer 806. Woven structural fiber layers 808, 810 are then overlaid overgelcoat layer 806. Woven structural fiber layers 808, 810 preferablycomprise a material designated Spectra 1000, available from Allied Fiberdivision of Allied Signal Corp. This material comprises a #985 PT(plasma treated) woven fabric of extended chain polyethylene fiberswhich are generally in the class of materials known as ballistic fibers.Another material in this class which may also be used for layers 808,810, comprises KEVLAR brand aramid fiber material, available fromDuPont. from Dupont. In the preferred practice of the present invention,woven structural fiber layers 808, 810 are approximately 0.020 inchesthick. Once layers 808, 810 are laid in mold 804, a layer of foam corematerial 812 is placed over the planar area of the structure. Foam corelayer 812 does not cover side wall areas 814, 816. Foam core layer 812is preferably of type LMP foam, type number CCL100, available by WindsorFiberglass, Inc. A layer of structural fibers 818 is then overlaid overfoam core layer 812. Structural fiber layer 818 is comprises the samematerial as structural fiber layers 808, 810. An electricallyconductive, magnetic shielding layer 820 is then overlaid overstructural fiber layer 818. Shielding layer 820 preferably comprisesexpanded copper foil 077 mesh, available from Dellcer Corp., Branford,Conn. Layer 820 is preferably 0.002-0.012 inches thick. Finally, anotherlayer or woven structural fibers 822 is overlaid over shielding layer820 wherein woven structural fiber layer 822 comprises the same materialused in fiber layers 808, 810 and 818. Once the respective layers arearranged in mold 804, they are enclosed between molds 802, 804 and therespective molds are held under slight pressure to compress therespective layers to within 0.100 inches thick. A thermoset resin(represented by arrows 826) is then injected through the injection port828 into the layers between the respective molds 802, 804 in a processreferred to as resin transfer molding. As the resin is injected into thestructure under pressure, at the center of the molds, air contained inthe respective layers is forced out at the perimeter as the air isreplaced by resin. The respective layers are then completelyencapsulated by resin. In the preferred practice of the presentinvention, a resin designated MODAR brand of modified acrylic resin,#835ACS, available from ICI Acrylics KSM, Inc. is used in the injectionprocess.

After an appropriate cure cycle time, the respective mold sections areseparated resulting in structure 850 shown in FIG. 14B. After removalfrom the mold, the edges of the port may be cut to expose the shieldingmaterial and coated with a permanent conductive coating to enable theshielding of the mating parts 12 ×14 to be electrically joined duringassembly. The connector plate 122 may also be electrically connected tothe shielding material in the outer housing member in the same fashionto enable connection of the shielding to ground plane of the internalcomponents. Those skilled in the art will appreciate that the process800 may be adapted to construct housing members of virtually anyconfiguration and the structure 850 may be readily drilled for formingapertures for mounting components and readily adhered to for attachingmounting structures or finishing appliances. The structure 850 is bothlightweight and extremely resilient and can readily withstand impacts ofextreme force.

In summary, an improved modular computer system has been described. Themodular computer system of the present invention provides a system whichmay be used as a stand alone workslate or may be used with a base unitin a desktop mode. The modular computer system of the present inventionincludes a housing structure which is substantially immune toenvironmental degregation and which highly resistant to mechanicalshocks. Accordingly, other uses and modifications of the presentinvention will be readily apparent to persons of ordinary skill and allof such uses and modifications are intended to fall within the scope ofthe appended claims.

We claim:
 1. An improved modular computer system, comprising:a selfcontained workslate unit including a first housing, said housingcontaining a display unit visible through said first housing; adigitizer disposed in cooperative engagement with said display unit; acomputer system having a data and address bus, serial and parallel portsand a keyboard interface, said computer system capable of outputtingdisplay data to said display unit, receiving input data from saiddigitizer, and providing computer functions to a user; and a mass datastorage device coupled to said computer system; said workslate unitfurther including first connector means, said first connector meansproviding a first set of connections to said data and address bus, saidserial and parallel ports and said keyboard interface; and a base unitincluding a second housing said base unit detachably connected to saidself contained workslate unit, said second housing containing akeyboard; an expansion area for supporting one or more peripheraldevices, and interlock means to detachably engage said workslate unit,said interlock means including second connector means for coupling tosaid first connector means to detachably provide electrical connectionsfor said keyboard and said one or more peripheral devices to said firstset of connections, said interlock means further including means formechanically attaching said workslate unit to said desktop base unit andfor supporting said workslate unit at a specific display viewing anglerelative to said base unit and simultaneously connecting said first andsecond connector means.
 2. The apparatus of claim 1, wherein saidworkslate unit further includes a plurality of apertures for receivingsupport means.
 3. The apparatus of claim 2, wherein said interlock meanscomprises a support flange pivotally mounted on said base unit with aplurality of bracket means, means for securing said second connectormeans to said support flange and a plurality of support posts coupled tosaid support flange on opposing sides of said second connector means,said support posts for cooperating with said plurality of apertures ofsaid workslate unit for attaching said workslate unit to said supportflange.
 4. The apparatus of claim 3, wherein said support posts includemeans for releasably latching said support posts within said pluralityof apertures.
 5. The apparatus of claim 4, wherein said support flangeincludes a plurality of angular adjustment arms disposed on opposingends of said support flange; each of said angular adjustment arms beingdisposed with a face normal to axis of rotation of said support flange;and said plurality of brackets includes spring biased ball bearings forengaging a plurality of angularly offset detents disposed in the face ofsaid angular adjustment arms.
 6. The apparatus of claim 1, wherein saidbase unit further includes third connector means coupled to said secondconnector means for providing expansion connections for said address anddata bus of said computer system.